The present invention relates to a slotted tube injector for an intraocular lens, and more particularly to a slotted tube for partial insertion in a minimum size incision to inject into the eye a temporarily folded, i.e. deformable, lens with opposed haptics, and means to fold the lens into the tube so that the haptics protrude from the tube slot, and to unfold the lens out of the tube in the eye for release, in controlled manner.
In eye surgery for treating conditions such as natural eye lens cataracts, a common procedure is to remove the cataracted lens through an incision in the cornea of the eyeball, and replace it by an artificial intraocular lens. The intraocular lens, typically 6 mm in diameter, is usually temporarily resiliently deformable, i.e. foldable into generally cylindrical shape, by curling, etc., to reduce its girth, and while kept folded is inserted through a corneal incision, typically 3.5-4 mm long, to minimize patient trauma. The lens has a lens body or optic, e.g. of soft material such as silicone, with normally stiffer resiliently deformable position fixation means or haptics, e.g. of polypropylene, extending therefrom to seat the lens in the eye.
The haptics must be kept in stable relation to the folded lens body during insertion into the eye so as to pass without difficulty through the incision. Once inserted, unfolding the lens body and haptics in the confined space at the implantation site must be controlled to avoid patient trauma from contact of these expanding mechanical elements with the inner wall of the cornea or other eye parts. Inserting the folded lens into an eye so as to minimize patient trauma is very difficult. A tool is needed to hold and insert the folded lens, requiring an incision large enough to accommodate both. Often, a separate retainer keeps the lens folded, so that the inserted retainer and tool clutter the eye interior during lens unfolding, after which the tool and retainer must be retrieved via the incision.
U.S. Pat. No. 4,573,998 to Mazzocco shows tools to insert a deformable lens into the eye by pushing, stretching, ejecting or compressing action. On insertion, the lens and/or tools grossly contact the eye incision, and the lens must be released carefully to keep it from injuring internal eye parts as it expands.
U.S. Pat. No. 4,906,247 to Fritch shows a deformable lens held folded by forceps inserted in a stretchable plastic tube so as to stretch the tube diameter and squeeze the tube around the folded lens like a mitten. On insertion via an incision into the eye, the forceps must release the lens carefully to keep it from injuring internal eye parts as it expands.
U.S. Pat. No. 4,911,714 to Poley shows a deformable lens held folded by sutures connecting apertures on opposed edges of the lens, or by integral lock means or adhesive on such edges, for insertion by a first tool through a first incision into the eye. A second tool inserted through a second incision is used to cut and remove the sutures, unlock the lock means or break the adhesive bond while the first tool holds the lens to keep it from injuring internal eye parts as it expands.
U.S. Pat. No. 4,917,680 to Poley shows a deformable lens held folded by a severable retainer or band for insertion by a first tool through a first incision into the eye. A second tool inserted through a second incision is used to sever and remove the band while the first tool holds the lens to keep it from injuring internal eye parts as it expands.
U.S. Pat. No. 4,976,716 to Cumming shows an injector having inner and outer tubes, and a plunger in the inner tube, for a deformable lens with leading and trailing haptics. Two flexible, widely diverging, inner fingers integral with the inner tube front are notched near their free ends to form bendable tips. Two rigid outer fingers, pivoted to the outer tube front, lock the inner fingers in narrower diverging state for retracting the inner tube in the outer tube so that only its tips protrude. Jaws of a loader squeeze and fold the lens between the inner fingers so that the leading haptic protrudes from their narrower diverging tips, and then the outer fingers are locked and the leading haptic and diverging tips inserted in the eye incision.
A drive moves the inner tube and plunger forwardly of the outer tube for the inner finger notches to clear the incision and the stored force of the folded lens to bend the inner finger tips outwardly of their widely diverging position to unfold the lens partially. The drive then moves the plunger for pushing the lens beyond the inner finger tips to unfold it completely. A return spring retracts the plunger and inner tube from the incision. The unit is complex, costly and cumbersome to operate, and its diverging fingers stress the incision or require use of a larger incision. As the fingers do not surround the folded lens, but only hold its diametrically opposed girth portions, the outwardly projecting girth portions therebetween can contact and stress the incision and inner cornea wall during the insertion procedure.
U.S. Pat. No. 4,836,201 to Patton et al shows an injector with a tubular tip in which an outer curlable petal and inner shaft having a front finger extend and retract. A deformable lens having leading and trailing haptics is lodged between the extended uncurled petal and finger with its trailing haptic at the petal rear and leading haptic extending from the petal front. The petal and finger retract to curl the lens in the petal while the leading haptic protrudes from the tubular tip. On inserting the tip in an eye incision, the petal and shaft extend to uncurl the lens, and the petal retracts from the finger to release the lens. The unit is complex and the trailing haptic obviously jams at the petal and tip during retraction and extension action.
An injector made by Allergen Inc., known as "The Prodigy," has a tubular tip inserted in an eye incision to inject a folded lens into the eye, but has no means to control lens unfolding.
U.S. Pat. No. 940,519 to Eastman shows an inserter tube with a slot from its open end almost to its closed end to load a tampon in the open end by a cord pulled along the slot, for ejection by a plunger. The tampon remains unfolded throughout.
U.S. Pat. No. 2,351,836 to Popper shows an inserter tube with a slot from one open end to the other to load a tampon by a cord pulled along the slot. On insertion in the vagina, the tube is peeled away at its slot to remove it from the tampon. Also shown is a tube slidably holding a prefolded tampon seated in a detainer well having a tab protruding from a slot spaced from the tube ends. On insertion, the tab is held to immobilize the well and the tube retracted to unfold the tampon partly from the well to engage the vaginal walls. The well undesirably tends to carry the tampon outwardly with it as it is removed with the tube.
It is desirable to insert a temporarily folded intraocular lens via a minimum size incision into the eye by an instrument that does not unduly stress or traumatize the incision, permitting controlled gradual lens injection and unfolding in the eye to avoid incision trauma from such stress or contact of the unfolding lens with the cornea inner wall or other eye parts.